Messages in this thread | | | Date | Fri, 29 Aug 2003 13:20:01 -0700 (PDT) | From | Shantanu Goel <> | Subject | Re: [VM PATCH] Faster reclamation of dirty pages and unused inode/dcache entries in 2.4.22 |
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Thanks for the pointer to the benchmarks.
The patch I posted only helps the mmap case so it won't help (or hurt hopefully ;-) any program that primarily does read/write instead of mmap. The extreme case where I observed this was a perl script that created a gigantic hash and tried to populate it. The perl in question uses mmap for malloc. The difference in execution time between stock 2.4.22 and one with the patch was insignificant because it is primarily I/O bound, however the other apps I was running, Mozilla and several xterm's, were paged out much less frequently in the latter case. The machine has 256MB of memory and perl grew to about 1 GB.
I have written another patch that more aggresively tries to free pages with dirty buffers which should help with the buffer I/O case. It essentially changes try_to_free_buffers() so it immediately starts and waits for I/O to complete if the gfp_mask allows it. It does not do any clustering so its performance is questionable at the moment.
--- Andrea Arcangeli <andrea@suse.de> wrote: > On Fri, Aug 29, 2003 at 12:46:36PM -0700, Shantanu > Goel wrote: > > Andrea, > > > > I'll test and submit a patch against -aa. Also, > is > > there a common benchmark that you use to test for > > regression? > > bonnie,tiobench,dbench would be a very good start > for the basics (note: > dbench can be misleading, but at the same fariness > levels, it's > interesting too, it's just that dbench doesn't > measure the fariness > level itself [like tiobench started doing relatively > recently]). > > (I'm assuming the patch makes difference not only > for mmapped dirty > pages, in such case the above would be non > interesting) > > thanks, > > Andrea
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